Extending our previous studies for the H2+OH reaction in five mathematical dimensions (5D) [J. Chem. Phys. 99, 5615 (1993); 100, 2697 (1994)], we present this paper a full-dimensional (6D) dynamics study title reaction. The 6D treatment uses time-dependent wave-packet approach and employs discrete variable representations three radial coordinates coupled angular momentum basis functions coordinates. an energy projection method to extract probabilities whole range of energies from single...

A more flexible neural network (NN) method using the fundamental invariants (FIs) as input vector is proposed in construction of potential energy surfaces for molecular systems involving identical atoms. Mathematically, FIs finitely generate permutation invariant polynomial (PIP) ring. In combination with NN, (FI-NN) can approximate any function to arbitrary accuracy. Because FI-NN minimizes size polynomials, it efficiently reduce evaluation time energy, particular polyatomic systems. this...

In this review, we survey the latest advances in theoretical understanding of bimolecular reaction dynamics past decade. The remarkable recent progress field has been driven by more accurate and efficient ab initio electronic structure theory, effective potential-energy surface fitting techniques, novel quantum scattering algorithms. Quantum mechanical characterization reactions continues to uncover interesting dynamical phenomena atom-diatom beyond, reaching an unprecedented level...

Reaction resonances, or transiently stabilized transition-state structures, have proven highly challenging to capture experimentally. Here, we used the sensitive H atom Rydberg tagging time-of-flight method conduct a crossed molecular beam scattering study of F + H2 --> HF reaction with full quantum-state resolution. Pronounced forward-scattered products in v' = 2 vibrational state were clearly observed at collision energy 0.52 kcal/mol; this was attributed both ground and first excited...

We show in this paper a time-dependent (TD) quantum wave packet calculation for the combustion reaction H+O2 using DMBE IV (double many-body expansion) potential energy surface which has deep well and supports long-lived resonances. The probabilities from initial states of H+O2(3Σ−g) (v=0–3, j=1) total angular momentum J=0 are obtained scattering energies threshold up to 2.5 eV, numerous resonance features. Our results that, by carrying out propagation several picoseconds, one can resolve...

A full quantum dynamical study of the reactions a hydrogen atom with water, on an accurate ab initio potential energy surface, is reported. The theoretical results are compared available experimental data for exchange and abstraction in H + D2O H2O. Clear agreement between theory experiment revealed thermal rate coefficients effects vibrational excitation reactants. excellent integral cross sections reaction unprecedented beyond atom-diatom reactions. However, larger than values by more...

A time-dependent wave packet method has been developed to study atom–triatom ABC+D→AB+CD reactions in full six dimensions (6D). The approach employs a body-fixed coupled angular momentum basis for three coordinates, and 1D bases radial coordinates. It permits the calculation of diatom AB vibrational state resolved total reaction probability an initial rovibrational triatom ABC. is applied H+H2O→H2+OH on modified Schatz–Elgersman potential energy surface. Initial state-selected probabilities...

A time-dependent wave packet method has been employed to compute initial state-specific total reaction probabilities for the benchmark H2+OH→H2O+H on modified Schatz–Elgersman potential energy surface which is derived from ab initio data. In our quantum treatment, OH bond length fixed but remaining five degrees of freedom are treated exactly in calculation. Initial title presented angular momentum J=0 and effects reagents rotation H2 vibration examined.

A global potential energy surface for the H2 + OH ↔ H2O H reaction has been constructed using neural networks method based on ~17,000 ab initio energies calculated at UCCSD(T)-F12a/AVTZ level of theory. Time-dependent wave packet calculations showed that new is very well converged with respect to number data points, as fitting process. Various tests revealed considerably more smooth and accurate than existing YZCL2 XXZ surfaces, representing best available benchmark four-atom system. Equally...

A new time-dependent wavepacket method is developed to study the + BC --> AB C, AC B reaction at state-to-state level. The only requires propagation of in reactant Jacobi coordinates by extracting S-matrix information on a dividing surface right before absorption potential product region. It has particular advantages for reactions with deep wells and long-range attractive interactions channels which can be absorbed sufficiently far away from interaction potential. Demonstration made...

Quantum dynamical theories have progressed to the stage in which state-to-state differential cross sections can now be routinely computed with high accuracy for three-atom systems since first such calculation was carried out more than 30 years ago H + H(2) system. For reactions beyond three atoms, however, highly accurate quantum calculations of not been feasible. We recently developed a wave packet method compute full-dimensional four-atom reactions. Here, we report benchmark prototypical...

The reaction of F with H 2 and its isotopomers is the paradigm for an exothermic triatomic abstraction reaction. In a crossed-beam scattering experiment, we determined relative integral differential cross sections ground F( P 3/2 ) excited F*( 1/2 spin-orbit states D collision energies 0.25 to 1.2 kilocalorie/mole. At lowest energy, F* ∼1.6 times more reactive than F, although forbidden within Born-Oppenheimer (BO) approximation. As energy increases, BO-allowed rapidly dominates. We found...

The S-matrix for a scattering system provides the most detailed information about dynamics. In this work, we discuss calculation of elements A+BC-->AB+C, AC+B type reaction. Two methods extracting from single wave packet in reactant Jacobi coordinates are reviewed and compared. Both capable state-to-state attributes both product channels propagation. It is shown through examples H+HD, Cl+H(2), H+HCl reactions that such coordinate based easy to implement, numerically efficient, accurate....

Pinpointing the role of geometric phase During chemical reactions, electrons usually rearrange more quickly than nuclei. Thus, theorists often adopt an adiabatic framework that considers vibrational and rotational dynamics within single electronic states. Near regime where two states intersect, get complicated, a factor is introduced to maintain simplifying power treatment. Yuan et al. conducted precise experimental measurements validate this approach. They studied elementary H + HD reaction...

Partial wave resonances, quasi-bound resonance states with well-defined rotation in the transition state region of a chemical reaction, play governing role reaction dynamics but have eluded direct experimental characterization. Here, we report observation individual partial resolved resonances F + HD --> HF D by measuring collision energy-dependent, angle- and state-resolved differential cross section extremely high resolution, providing spectroscopic probe to D. The agreement data...

Experimental limitations in vibrational excitation efficiency have previously hindered investigation of how energy might mediate the role dynamical resonances bimolecular reactions. Here, we report on a high-resolution crossed-molecular-beam experiment vibrationally excited HD(v = 1) + F → HF D reaction, which two broad peaks for backward-scattered HF(v' 2 and 3) products clearly emerge at collision energies 0.21 kilocalories per mole (kcal/mol) 0.62 kcal/mol from differential cross sections...

The Polanyi rules, which state that vibrational energy is more efficient in promoting a late-barrier reaction than translational energy, were questioned recently by an experimental unexpected finding the CH stretch excitation no effective Cl + CHD3 energy. However, present quantum dynamics study on best-available potential surface for title reveals does promote significantly, except at low collision energies. Further studies should be carried out to solve disagreements between theory and...

We report a new global potential energy surface of the HOCO system based on F12 correction unrestricted coupled-cluster with singles doubles and approximative triples using augmented correlation-consistent polarized valence triple-zeta basis set (UCCSD(T)-F12/AVTZ), fitted by neural networks. Quantum dynamics calculations confirmed satisfactory convergence respect to number data points fitting process. It is found that total reaction probabilities complex-formation obtained present differ...

A few very brief pauses in the action Chemical reactions proceed by cumulative effect of trillions upon collisions between atoms and molecules. Usually, a given collision bounces participants right back out again, either their original form or with shuffled around into distinct products. In certain cases, reacting partners experience lull, termed resonance, before they rearrange. Yang et al. report discovery particularly short-lived resonances reactive chlorine vibrationally excited hydrogen...

There has been great progress in the development of potential energy surfaces (PESs) and quantum dynamics calculations gas phase. The establishment a fitting procedure for highly accurate PESs new developments reactive scattering on reliable allow characterization reaction beyond triatomic systems. This review will give recent our group constructing ab initio based neural networks time-dependent wave packet bimolecular reactions three atoms. Bimolecular current interest to community, namely,...

Symmetry adaptation is crucial in representing a permutationally invariant potential energy surface (PES). Due to the rapid increase computational time with respect molecular size, as well reliance on algebra software, previous neural network (NN) fitting inputs of fundamental invariants (FIs) has practical limits. Here, we report an improved and efficient generation scheme FIs based theory parallel program, which can be readily used input vector NNs high-dimensional PESs permutation...

Conversion of carbon monoxide to high value-added ethylene with selectivity by traditional syngas conversion process is challenging because the limitation Anderson-Schulz-Flory distribution. Herein we report a direct electrocatalytic for highly selective production from CO reduction water over Cu catalysts at room temperature and ambient pressure. An unprecedented 52.7 % Faradaic efficiency formation achieved through optimization cathode structure facilitate diffusion surface electrode...

Abstract Traditional water–gas shift reaction provides one primary route for industrial production of clean-energy hydrogen. However, this process operates at high temperatures and pressures, requires additional separation H 2 from products containing CO , CH 4 residual CO. Herein, we report a room-temperature electrochemical direct purity hydrogen (over 99.99%) with faradaic efficiency approximately 100%. Through rational design anode structure to facilitate diffusion PtCu catalyst optimize...

Infrared spectroscopic study of neutral water clusters is crucial to understanding the hydrogen-bonding networks in liquid and ice. Here we report infrared spectra size-selected clusters, (H2O) n (n = 3-6), OH stretching vibration region, based on threshold photoionization using a tunable vacuum ultraviolet free-electron laser. Distinct stretch vibrational fundamentals observed 3,500-3,600-cm-1 region (H2O)5 provide unique spectral signatures for formation noncyclic pentamer, which coexists...

Prealigning nonpolar reacting molecules leads to large stereodynamical effects because of their weak steering interaction en route the reaction barrier. However, experimental limitations in preparing aligned efficiently have hindered investigation steric bimolecular reactions involving hydrogen. Here, we report a high-resolution crossed-beam study H + HD(v = 1, j 2) → H2(v', j') D at collision energies 0.50, 1.20, and 2.07 electron volts which vibrationally excited hydrogen deuteride (HD)...